Alcoholism is a serious human health issue and it has been predicted that it will affect about 16% of the population. Mortality rates among alcoholics are two to three times the rate for the general population and it has been suggested that it is one of the leading preventable causes of death, injury, illness and impaired functioning. In 1987, the National Institute on Alcoholism and Alcohol Abuse cited reports estimating the total societal costs for alcoholism in 1983 of about $116 billion dollars.
There are four known, major techniques for diagnosing alcoholism or excessive drinking. One of these involves the examination of blood serum variables and the remaining three involve psychological assessment.
An example of earlier work based on examination of blood serum variables is described in a paper titled "Biochemical and Hematological Correlates of Alcoholism" by Ryback et al. published in Research Communications in Chemical Pathology and Pharmacology. Vol. 27, No. 3, Mar. 1980. The authors considered a number of blood serum constituents in several combinations. Best accuracy (86% in the combined alcoholic group) resulted when they used the SMA 12 (12 standard constituents), SMA 6 (6 standard constituents) and Hematological (7 standard constituents) tests in combination. Table 2 of the paper shows the 25 total constituents although the authors refer in several places to the "24 tests." The authors experienced 16% "false negatives," i.e., 16% of the alcoholics were identified as being nonalcoholics. No "false positives" were experienced.
Two aspects of the Ryback et al. paper are particularly important. One is that the "prior probabilities" (a reflection of apparent historical fact) used by the authors were 0.5 for medical controls, 0.4 for treatment program alcoholics and 0.1 for alcoholics admitted to medical wards. These values were selected "arbitrarily" but were influenced by a study which indicated that about 50% of a group of patients admitted to a Veterans Hospital had alcohol related problems.
The authors further indicate that adjustment of the prior probabilities by + or -0.1 resulted in no significant change in the accuracy of the discrimination between alcoholics and nonalcoholics. They also stated that "[t]he prior probabilities could be changed from 0.4 to 0.8 in the medical controls and from 0.6 to 0.2 in the alcoholics with no significant change in the accuracy of discrimination."
The other particularly important aspect of the Ryback et al. paper is a quotation appearing on page 545. There, the authors state that "[s]ignificant relationships involving drinking variables were observed for all tests except cholesterol . . . " (emphasis added).
Another relevant paper dealing with examination of blood serum variables is titled "Hematological Concomitants of Alcoholism: Development and Validation of a Clinical Screening Technique" by Hawkins et al. published in Journal of Substance Abuse Treatment, Vol. 1, 1984. While the age and sex of the subjects were noted, no observation was made as to whether such factors are of use in identifying abuse. Hawkins et al. used two different multivariate discriminant analyses which yielded classification accuracies significantly different from one another. The quadratic analysis correctly classified about 94% of alcoholics while the "stepwise" analysis correctly classified about 79% of alcoholics.
The authors' caveat states". . . this technique is unlikely to provide sufficiently precise classification for anything other than medical screening purposes, which should then be bolstered with independent substantiation before arriving at a diagnosis."
Some of the earlier work involving analysis of blood serum variables considers the blood chemistry constituents selenium and magnesium. Such work is described in a paper titled "Diminished Blood Selenium Levels in Alcoholics" by Dworkin et al. published in Alcoholism: Clinical and Experimental Research, Vol. 8, No. 6, Nov./Dec. 1984. The authors have noted that alcoholics have a reduced level of selenium. As stated in the Abstract, this fact is of concern to the authors "[s]ince selenium deficiency can produce a spectrum of organ injury . . . the relationship of selenium deficiency to alcohol-induced organ injury deserves further study."
Clearly, the subjects had already been identified as alcohol abusers--the focus of the research was prospective organ damage. And the authors observe that low selenium levels can also result from diet, cancer, severe burns and kwashiorkor. In other words, a low selenium blood serum level per se was not appreciated as having value in the diagnosis of alcohol abuse. A similar paper is "Decreased Serum Selenium in Alcoholics as Related to Liver Structure and Function" by Korpela et al. published in The American Journal of Clinical Nutrition, Jul. 1985.
Other work involving blood serum variables is described in a paper titled "Serum Zinc, Copper, and Ceruloplasmin Levels in Male Alcoholics" by Wu et al. published in Biological Psychiatry, Vol. 19, NO. 9, 1984. The authors used blood samples from known alcoholics having an average daily consumption level of about 294 mL of absolute alcohol. They noted the reciprocal relationship between serum zinc and copper levels and found that the serum zinc level in alcoholic patients was lower than that of a control group. While the serum copper level was higher, the authors indicate it was not statistically significant. The authors also observe that earlier workers have found a psychiatric condition, i.e., depression, to be associated with lower serum zinc levels and low zinc, copper and ceruloplasmin levels. In an added note, the authors also state, with respect to serum levels of calcium and magnesium, that "[t]heir differences were not statistically significant between alcoholics and controls."
Yet another paper dealing with blood serum variables is titled "Alcohol Consumption and High Density Lipoprotein Cholesterol Concentration Among Alcoholics" by Dai et al. published in American Journal of Epidemiology, Vol. 122, No. 4, 1985. In the Abstract, the authors note that HDL cholesterol increased with increasing alcohol consumption up to about 450 mL of ethanol consumption per day. Above such consumption level, HDL cholesterol level decreased or appeared to decrease. The authors primarily examined the relationship between alcohol consumption and the level of HDL subclasses HDL2 and HDL3.
Currently, most persons suspected of having a drinking problem are screened using psychological tests, some of which are mentioned below. A frequent difficulty with such tests is that their results depend heavily upon the subject's "good will," i.e., information as voluntarily disclosed by the subject. Since denial is a frequent trait of alcoholics, such information can be "skewed" and accuracy of diagnosis suffers.
One psychological approach, empirical in nature, is known as the MacAndrew scale of the Minnesota MultiPhasic Personality Inventory (MMPI). The MacAndrew scale is generally accepted as a reliable method of alcohol assessment. It has been demonstrated to correctly classify about 84% of alcoholics when a cutoff score of 24 raw points is used. There are about 10 false negatives and 14 false positives using such cutoff point.
In general, the MacAndrew test is composed of those items from the MMPI to which alcoholics respond differently than does the general population. The subject is required to respond to "true" or "false" questions which include latent "check" questions to detect whether the subject has answered consistently. The accuracy of the MacAndrew scale has been questioned since it also seems to respond to other forms of drug addiction as well as to general deviancy.
It should be appreciated that when tests are used for certain purposes, e.g., screening job applicants, "false positives" present a certain risk for the tester. The applicant may be denied a job, perhaps one of substantial responsibility, if s/he is falsely said to be alcoholic. The authors of the aforementioned Ryback et al. paper refer to this happenstance as "clinically embarrassing."
On the other hand, there are situations where a false positive causes little or no adversity to anyone but the risk of a false negative is relatively great. For example, alcoholism in persons under consideration for alcoholism treatment should be identified with a relatively high level of certainty. Another example involves selection of persons for highly sensitive tasks requiring, e.g., certain unusual physical skills or a high level of secrecy. The public interest in selection accuracy may be sufficiently high so as to outweigh considerations of adversity arising from a false positive. In those instances, the sole question is whether the subject is drinking alcoholically rather than how much (within quantity ranges) the subject is drinking. Identification of such individuals is by using only two prior probability values, namely, 0.5 and 0.5 rather than the more typical 0.9 and 0.1 values. As described herein in connection with the invention, the use of three prior probability values aids in identifying how much the subject is drinking.
Another psychological approach involves the use of "consumption pattern" questionnaires. The Khavari Alcohol Test is an example of such an approach. In studies of validity and reliability, the Khavari test has consistently and relatively accurately differentiated between alcoholic and control groups. The Khavari test considers the drinking patterns of individuals (as provided by such individuals) and compares such patterns with established statistical drinking norms. These comparisons are then used for making diagnostic decisions.
Yet another psychological approach involves a variety of questionnaires which attempt to count incidents of problems or behaviors thought to be symptomatic of alcoholism. The Michigan Alcoholism Screening Test (MAST), and the National Council on Alcoholism Criteria for the Diagnosis of Alcoholism (CRIT) are examples. In a modified form known as MODCRIT, the latter is used clinically.
U.S. Pat. Nos. 3,954,409 (Hsia), 3,645,688 (Smernoff), 4,115,062 (Morre et al.), 4,820,628 (Weitz), 4,753,890 (Smith-Lewis et al.), 4,820,647 (Gibbons) and 4,837,164 (Glick) describe methods for analyzing blood serum constituents. Such patents do not suggest how such methods might be used for determining the consumption rate of alcohol or for diagnosing alcoholism.
The Smernoff and Hsia patents involve cholesterol in blood and describe methods for recognizing the type and presence of hyperlipoproteinemia (Smernoff) or for assessing the risk of coronary heart disease (Hsia). The Smith-Lewis et al. patent describes a method for determining magnesium ions in, among other things, blood serum and plasma. While the patent says the determination of such ion can be used for diagnosing and treating "various ailments," alcohol abuse is neither mentioned nor suggested.
An aspect of the earlier work described above may be summarized by observing that it fails to appreciate how the actual "level" or rate (within somewhat broad ranges) at which an individual is consuming ethanol alcohol can be relatively quickly determined by analyzing the serum variables in a blood sample taken from such individual. A method for making such a determination would be an important advance in diagnosing alcoholism. This is especially true if the level of accuracy is sufficient to permit the method to be the sole, or at least predominant, clinical tool in diagnosing alcoholism.